1. Field of the Invention
The present invention relates to a paging receiver having a vibration mode, and more particularly to a paging receiver and a sequential vibrating method therefore wherein the vibration level of a motor is sequentially adjusted when a call is transmitted to a paging receiver operating in a vibration mode.
2. Description of the Related Art
Generally, a paging receiver is used to store a message received to its address, when a call, transmitted from an external telephone source, is received. To alert a user of the paging receiver that call has been received, the paging receiver may provide an audible alarm or tactual alarm, and at the same time a received message is displayed. The received message is also stored in an internal memory which can be accessed by the user pressing a read key, if necessary. When the paging receiver is operating in the audible alarm mode, a warning sound informing a user that a call has been received, is generated. When the paging receiver is operating in the tactual alarm mode the body of the paging receiver vibrates, so that the user can be alerted to a received call by the sensing the vibrations.
A conventional paging receiver may include an eccentrically rotating motor which causes the body of the paging receiver to vibrate due to the motor's change of its center of gravity as it rotates. One such paging receiver is discussed in U.S. Pat. No. 5,471,103 by Masahiro Fujii, entitled Motor For Providing A Vibrating Action For A Radio Pager. This patent discusses the how the change in mass of the of a rotor of the motor will increase the degree of vibration of the pager receiver.
Accordingly, other paging receivers provide a weak vibration level which may or may not be sensed by the user, either due to the user's sensitivity to the vibrations or due to how the paging receiver is carried. Additionally, a user may be easily startled by the sudden start of a vibration mode when a call is received by a paging receiver having a strong vibrational level.